Device for letting down mainsprings



(No Model.)

0. BIGKFORD.

DEVICE FOR LETTING DOWN MAINSPRINGS. v No. 360,648.

Patented Apr. 5, 1887.

WiTPlEEESi-ZS N. Pains Phmum w'. Washington. D. c

' UNITED STATES PATENT OFFICE.

CHARLES BIOKFORD, OF BOSTON, MASSACHUSETTS.

DEVICE FOR LETTING DOWN MAINSPRINGS.

SPECIFICATION forming part of Letters Patent NC. 360,648, dated April 5,1887.

Application filed April 29, 1856. Serial No. 200,506. (No model.)

To all whom it may concern.-

Be it known that I, CHARLES BIoKFoRD, of Boston, in the county ofSuffolk and State of Massachusetts, have invented certain new and usefulImprovements in Devices for Letting Down WVinding-Springs, of which thefollowing is a specification.

This invention has for its object to enable the winding spring orsprings of a clock or watch to be conveniently unwound or let down; andto this end it consists in the combination, with a winding-arbor and theusual ratchet-thereon, of a pawl which is normally engaged with saidratchet and prevents the backward or letting-down movement of thespring, as usual, and a detent whereby said pawl may be held out ofengagement with the ratchet, and therebypermit the letting down of thespring engaged with said arbor, as I will now proceed to describe andclaim.

Of the accompanying drawings, forming a part of this specification,Figure 1 represents a side elevation of a clock-winding mechanism towhich my improvement is applicable. Fig. 2 represents a sectional viewof the same. Fig. 3 represents a section on line 3/ y, Fig. 2, lookingtoward the right, the ratchet ot the winding-arbor being in engagementwith its pawl. Fig. 4: represents a similar section,the pawl being heldout of engagement with the ratchet by its detent. Figs. 5 and 6represent, respectively, portions of Figs. 3 and 4 on an enlarged scale.

The same letters of reference indicate the same parts in all thefigures.

In the drawings I have shown my improvement in connectionwith a windingmechanism (not of my invention) in which two mainsprings, a and a, areemployed, attached at their inner ends to arbors d d in line with eachother, and at their outer ends to drums I) I), having gears c c,actuating separate trains of wheel-work, one of said gears actuating thetime-movement and the other the strikingmovement of a clock.

On the arbors d d are ratchets e e, connected to said arbors, so as torotate therewith, the teeth of said ratchets being inclined in oppositedirections. The ratchets echave between them a pawl-carrier, 9, (shownas a disk,) attached to a key-shaft,h,which extends through and is freeto rotate in the arbors d (1, said arbors being made tubular for thepurpose.

The pawl-carrier g, on the side adjacent to the ratchet e,is providedwith a winding-pawl, i, adapted to engage the teeth of the ratchet ewhen the pawl-carrier is turned in one direction, and the saidpawl-carrier is provided at its other end with a similar winding-pawl,which engages the teeth of the ratchet 6 when the pawl-carrier is turnedin the opposite direction. This mechanism, which is not of my invention,enables the two springs to be wound alternately by a key applied to theshaft h, the shaft being oscillated or turned first in one direction andthen in the opposite direction.

In carrying out my invention I provide each of the pawls '6 13 with atooth or shoulder, i", and secure to the pawl-carrier latches or detentsj", adapted to automatically engage the said shoulders when thepawls are turned away from the ratchets, and hold the pawls in inoperative positions, as shown in Fig. 4. Pr0- vision is thus made forconveniently letting down either of the springs, either pawl beingautomatically retained when disengaged from its ratchet-holdingposition.

This improvement is not limited to the special winding mechanism hereindescribed, but may be used in connection with any kind of windingmechanism.

The pawl i may be disengaged from the ratchet-wheel by any suitable tooladapted to be pressed against the ratchet. A special tool having a hookor offset at one end may be used for this purpose.

I claim- 1. The combination, with a winding-spring, its arbor, and theratchet thereon, of a shonldered pawl normally engaged with said ratchetand a spring-detent which automatically engages with the pawl and holdsit in an inoperative position when it (the said pawl) is separated fromthe ratchet, as set forth.

2. The combination, with the two independent springs,their arbors, andthe ratchets there on, of the pawl-carrier having the two pawls normallyengaged with said ratchets and the detents whereby said pawls may beheld out of engagement with the ratehets,.as set forth.

In testimony whereofI have signed my name to this specification, in thepresence of two subscribing witnesses, this 27th day of April, 1886.

CHARLES BIGKFORD.

Witnesses:

ARTHUR W. GRossLEY, A. D. HARRISON.

